1. Field of Invention
The invention concerns a shock-absorbent lining element for the interior of a vehicle. More specifically, the invention concerns an armrest for vehicles, which can be used, e.g., in the inner linings of doors or fixed side elements.
2. Prior Art
Vehicle doors typically consist of an outer metal panel and an inner metal panel, which are connected to each other, and the outer sides of the component also form a decorative inner lining as a border to the passenger compartment. For reinforcing the doors with reference to improving side-impact behavior, a reinforcing profiled section is often arranged on the inner side of the outer metal panel at a height approximately in the middle. Between the outer and inner sides there are functional elements, such as, e.g., window-raising systems, loudspeakers, locks, and if necessary, other elements, which are frequently mounted on their own module supports. These functional elements are mentioned for completeness, but they play no role with reference to the invention.
The inner lining typically carries an arm support, which consists of a rigid support, a relatively hard foam layer, which lies on top of the support and which provides a pleasant feel, and a sealing decorative layer, which faces the passenger compartment and which is made of leather, synthetic leather, textile, or plastic film. The armrest often projects past the surface of the inner lining into the passenger compartment, in height somewhere between the edge of the hips and the lower ribs of the vehicle occupant. If there is a side impact, the entire vehicle door is pressed inwards in the direction of the vehicle occupant. The reinforcing profiled section cannot completely prevent this inward pressing force. Thus, there is a large danger that the armrest extending past the surface of the side lining could be pressed into the mentioned region of the upper body of the vehicle occupant and cause considerable injury, even with the presence of so-called side airbags, which can be deployed outwards from the inner lining or from the seat. This risk of injury is considerably reduced if the force, with which the armrest is pressed against the body during deformation, does not exceed 1000 N. This also corresponds to the new requirements for automotive manufacturers.
Constructions for deformable arm supports, which, e.g., consist of plastic support material and which include intended rupture points in the support material, are known. A disadvantage here is that a rupture of the support material, particularly if it is brittle, can produce sharp edges and splinters, which can penetrate through the decorative material and can thus cause additional risk of injury. It has been shown that the breaking behavior of these intended rupture points is strongly dependent on temperature in an undesired way.
Constructions with laminar support parts, which can move relative to each other, have also proven to be unsuitable. If the support is composed of individual layers that loosely grip one another, then it does not provide the necessary stability required by a support layer for arm supports. The connection of the support layer to the decorative layer by means of a known foam lamination method with, e.g., polyurethane, which represents an economical method often used for this purpose, has not shown the desired successful results. The foam does indeed stabilize the layers and it also absorbs energy in the case of deformation, but it also springs back due to its elasticity. A reduction of force to the vehicle occupant is thus not achieved.
By connecting the layers to cross-pieces formed as intended rupture points, the stability of the support is increased, but this also produces the disadvantages mentioned above with reference to intended rupture points.
Constructions with open honeycomb structures set perpendicular to the direction of deformation would allow very good energy absorption. However, they are unsuitable because they lose their good deformation properties in the foam lamination process either due to elastic foam penetrating into the honeycomb structures or due to cover layers preventing foam penetration. With reference to the elastic foam in the case of penetration into the honeycomb structures, there results the same state as for foam-covered layers.
From U.S. Pat. No. 5,181,759A, DE-AS 1 267 116, and DE 41 40 706 A1, armrests are known which, however, do not sufficiently absorb energy transmitted due to an external force.
According to DE 30 26 736 A1, deformation of an armrest is achieved in that the walls of a projecting region have zones of reduced wall thickness for the purpose of forming intended rupture points or intended bending points. Therefore, intended rupture points are formed so that for an impact on a projecting region, these points break, so that the jacket elements become nested between the notches.
The main object of the invention is to provide an arm support, which deforms on impact with the body of the vehicle occupant such that the force exerted by the arm support on the body of the vehicle occupant in the region approximately between the edge of the hips and the lower ribs remains below the critical value of 1000 N, but which can also provide the required strength for support on the top side of the arm support.
The main object of the invention is accomplished, according to the invention, by using a lining element arranged on the side of a vehicle chassis part facing the interior with at least one section, which can be deformed due to the effect of an external force, and which is provided to absorb impact energy by transforming into a deformed state. The inventive improvement comprises a support layer being formed in the region of the deformable section from, viewed from the interior, an outer deformation part, an inner deformation part, and a step edge set between these parts, and the outer deformation part, the inner deformation part, and the step edge change their slope under the effect of the external force for energy absorption.
According to the invention, a lining element arranged on the side of a vehicle chassis part facing the interior with at least one deformation section, which is provided to absorb impact energy for the effect of an external force by transforming into a deformed state, that has been improved by having at least the deformation section formed from multiple layers from
a support layer from tough material,
a top layer facing the vehicle interior, and
a layer set between these layers, which is formed from elastic foam.
The support layer has a shock-absorbing region, which is set in the region of the deformation section and which is formed from, viewed from the interior, an outer deformation part, an inner deformation part, and a step edge, which is set between these parts and which runs at an angle range between 70-85 degrees relative to the inner deformation part, so that for an effect of the external force the angle between the outer deformation part and the inner deformation part is decreased for energy absorption.
The lining element is arranged on the side of a vehicle chassis part facing the interior as described above with the step depth given between the outer deformation part and the inner deformation part equal to 8.4 mm. In the preferred embodiment, the support layer is formed from wood fibers.
The invention includes the further improvement of (a) the outer deformation part and the inner deformation part being spaced a distance of from 7 to 9 mm perpendicular to the received force direction, (b) the material of the support layer having a density in the range of 0.5-0.7 g/cm3 and the support layer having a thickness in the range between 1.8-2.0 mm, (c) the support layer being formed from polyester fibers and from glued wood fibers, and wherein the polyester fibers constituting 20-25 wt % and the wood fibers constituting 80-75 wt %, and spruce, fir, or pine wood being used for the wood fibers, and also that the wood fibers having a fiber length of 0.1-2 cm. The fibers are glued with a binding agent comprised of a thermally cross-linkable acrylate resin, and the thermally cross-linkable acrylate resin is present from 10-15 wt % relative to the amount of wood fibers present.
One advantage of the invention is the simple manufacturing process of the arm support according to the invention. In comparison with the molds required today for production, the contours must be modified, which is possible without problems; however, usually no additional complicated moving parts are necessary in the mold, particularly in the press mold for the support. In comparison with conventional constructions, additional components in or on the armrest are not needed.
It is further advantageous that intended rupture points in the support material are not needed; these rupture points do not contribute significantly to energy absorption and also increase the risk of sharp end pieces or splintered parts severing the foam and decorative layer, and thus, increasing the risk of injury for the vehicle occupants.
Absorption of impact energy is achieved by the armrest according to the invention through deformation of the support. This gives the especially advantageous result that for deformation of the arm support, no elastic foam parts are pinched by the support and/or decorative material.
Corresponding to the requirements in each individual case, the arm support according to the invention can be manufactured either as a separate part, which is then connected to the lining during the assembly of the lining element, or else, in the case of an arm support integrated in the lining, the arm support is processed directly during the production of the support element.